Research on Water Suitability of Maize Planting Range in Northeast China

Soil Moisture plays an important role in regulating rainfall infiltration and surface evaporation. In this study, the monthly mean data (soil moisture, sunshine percentage, mean air temperature, mean wind speed, mean relative humidity, precipitation, and mean water vapor pressure) from 1961 to 2010 were provided by China Meteorological Data Network and the soil moisture products of four layers (0-10cm, 10-40cm, 40-100cm and 100-200cm) for 1948–2010 years were provided by GLDAS (Global Land Data Assimilation System). Based on these data, the error characteristics of GLDAS soil moisture products are evaluated. Crop water requirement is calculated based on the crop coefficient method by Penman-Monteith formula. The results showed that the soil water content of 0-200cm in the northeast region decreased in recent 60 years, and the whole northeast region decreased about 92 billion m³. Combined with the water demand of maize growing season, it can be seen that the water deficit boundary of maize planting moved eastward about 1.5 °. These results are of great significance for agricultural management in Northeast China in the future.